1. Field of the Invention
This invention relates to improvements in the calibration of broadband ultrasonic transducers. More particularly, this invention calibrates a broadband ultrasonic transducer without using another device as the standard and reduces the number of measurements required to calibrate the transducer.
2. Description of the Related Art
Broadband capacitive electrostatic acoustic transducers are used for absolute amplitude ultrasonic measurements in liquid environments. These transducers are air-tight enclosures with a conductive membrane as part of its outside surface. A central electrode that has a flat end is mounted inside the enclosure so that the flat end is approximately parallel to the conductive membrane. This forms a capacitor.
The frequency response of the electrostatic acoustic transducer (ESAT) has a frequency range from sub-MHz to above 15 MHz depending on the membrane. These ESATs can also be used to measure the absolute amplitudes of ultrasonic compressional waves in liquids. These measurement techniques make the ESAT especially useful in the study of ultrasonic properties of liquids, including liquid-state anharmonicity, ultrasonic dosimetry in medical and biological applications, and also ultrasonic spectral analysis.